Spinal stabilization device

Abstract

A bone attachment device comprises an attachment collar having a hinged lid is disclosed. The bone attachment device may also comprise a bone fastener (such as a bone screw). A bone attachment device including an attachment collar and a spinal rod locking device is disclosed. A bone attachment device as described herein may be used together with a spinal stabilization rod and one or more additional bone attachment devices. Such devices are adapted to clamp and hold a spinal stabilization rod. Methods for implanting a spinal stabilizer having a bone attachment device including a hinged lid are disclosed.

What is claimed is: 
     
       1. A bone attachment device, comprising:
 (a) a bone fastener having a distal portion adapted to pierce bone and a proximal portion having a head; 
 (b) a collar comprising:
 (i) a collar wall defining a cavity and having at least one wall aperture; 
 (ii) a distal portion comprising an opening and a collar seat projecting inward and supporting the head of the bone fastener; 
 (iii) a proximal portion having a hinged lid attached to the collar wall with a pivot pin, the hinged lid possessing a central aperture and a lid hook opposite the pivot in wherein the lid hook is adapted to engage a corresponding feature in the collar wall; and 
 (iv) a spinal rod locking device passing through the central aperture in the hinged lid, comprising:
 (A) a nut, the nut having an outer diameter, the nut being adapted to turn about an axis from an unlocked configuration to a locked configuration, and which possesses a distal cam surface and a collar engagement member projecting radially from only a segment of an outer diameter surface of the nut such that the collar engagement member does not extend around the entire outer diameter of the nut, wherein the distal cam surface is adapted to impart distal force to a clamp member and the collar engagement member is adapted to rotatably engage a collar overhang of the collar wall in the locked configuration and not engage the collar wall in the unlocked configuration; and 
 (B) the clamp member possessing a proximal cam surface, which interacts with the distal cam surface of the nut, and which is adapted to receive distal force from the nut and impart distal force to a rod extending through the at least one wall aperture; 
 wherein at least a portion of the spinal rod locking device is within the cavity defined by the collar wall. 
 
 
 
     
     
       2. The bone attachment device of  claim 1 , further comprising a washer. 
     
     
       3. The bone attachment device of  claim 2 , wherein the washer comprises a substantially cylindrical wall having an interior surface and an exterior surface; and the washer has a proximal end and a distal end. 
     
     
       4. The bone attachment device of  claim 3 , wherein the distal end of the washer fits over the head of the bone fastener. 
     
     
       5. The bone attachment device of  claim 1 , further comprising:
 a washer having a beveled surface at a distal end of the washer, wherein the beveled surface abuts the proximal portion of the bone fastener, 
 wherein the clamp member further comprises a distal surface, at least a portion of which is planar, convex or concave, and is adapted to engage the rod extending through the at least one wall aperture. 
 
     
     
       6. The bone attachment device of  claim 1 , further comprising:
 (b) a washer having a beveled surface at a distal end of the washer, wherein the beveled surface abuts the proximal portion of the bone fastener, wherein the beveled surface is planar frustoconical, 
 wherein the clamp member further comprises a distal surface, at least a portion of which is concave, and is adapted to engage the rod extending through the at least one wall aperture. 
 
     
     
       7. A spinal stabilizer, comprising:
 (a) at least two bone attachment devices, each of the at least two bone attachment devices comprising:
 (i) a bone fastener having a distal portion adapted to pierce bone and a proximal portion having a head; and 
 (ii) a collar comprising
 (A) a collar wall defining a cavity and having at least one wall aperture, 
 (B) a distal portion comprising an opening and a collar seat projecting inward and supporting the head of the bone fastener, 
 (C) a proximal portion having a hinged lid attached to the collar wall with a pivot pin, the hinged lid possessing a central aperture and a lid hook opposite the pivot pin wherein the lid hook is adapted to engage a corresponding feature in the collar wall; and 
 (D) a spinal rod locking device passing through the central aperture in the hinged lid, comprising:
 (1) a nut, the nut having an outer diameter, the nut being adapted to turn about an axis from an unlocked configuration to a locked configuration, and which possesses a distal cam surface and a collar engagement member projecting radially from only a segment of an outer diameter surface of the nut such that the collar engagement member does not extend around the entire outer diameter of the nut, wherein the distal cam surface is adapted to impart distal force to a clamp member and the collar engagement member is adapted to rotatably engage a collar overhang of the collar wall in the locked configuration and not engage the collar wall in the unlocked configuration; and 
 (2) the clamp member possessing a proximal cam surface, which interacts with the distal cam surface of the nut, and which is adapted to receive distal force from the nut; 
 
 wherein at least a portion of the spinal rod locking device is within the cavity defined by the collar wall; and 
 
 
 (b) a bone stabilization rod extending through the at least one wall aperture of each of the at least two bone attachment devices; 
 wherein the clamp member of each of the at least two bone attachment devices imparts a distal force to the bone stabilization rod; and 
 wherein the spinal rod locking devices are adapted to lock the bone stabilization rod in place, thereby preventing translational motion of the bone stabilization rod. 
 
     
     
       8. The spinal stabilizer of  claim 7 , further comprising a washer. 
     
     
       9. The spinal stabilizer of  claim 7 , wherein each of the bone attachment devices further comprises:
 a washer having a beveled surface at a distal end of the washer, wherein the beveled surface abuts the proximal portion of the bone fastener, 
 wherein the clamp member further comprises a distal surface, at least a portion of which is planar, convex or concave, and is adapted to engage the bone stabilization rod extending through the at least one wall aperture. 
 
     
     
       10. The spinal stabilizer of  claim 7 , wherein each of the bone attachment devices further comprises:
 a washer having a beveled surface at a distal end of the washer, wherein the beveled surface abuts the proximal portion of the bone fastener, wherein the beveled surface is planar frustoconical, 
 wherein the clamp member further comprises a distal surface, at least a portion of which is concave, and is adapted to engage the bone stabilization rod extending through the at least one wall aperture. 
 
     
     
       11. A bone attachment collar, comprising:
 (a) a collar wall defining a cavity and having at least one wall aperture; 
 (b) a distal portion comprising an opening and a collar seat projecting inward and supporting a head of a bone fastener; 
 (c) a proximal portion having a hinged lid attached to the collar wall with a pivot pin, the hinged lid possessing a central aperture and a lid hook opposite the the pivot pin wherein the lid hook is adapted to engage a corresponding feature in the collar wall; and 
 (d) a spinal rod locking device located at least partially within the central aperture in the hinged lid, comprising:
 (i) a nut, the nut having an outer diameter, the nut being adapted to turn about an axis from an unlocked configuration to a locked configuration, and which possesses a distal cam surface and a collar engagement member projecting radially from only a segment of an outer diameter surface of the nut such that the collar engagement member does not extend around the entire outer diameter of the nut, wherein the distal cam surface is adapted to impart distal force to a clamp member and the collar engagement member is adapted to rotatably engage a collar overhang of the collar wall in the locked configuration and not engage the collar wall in the unlocked configuration; and 
 (ii) the clamp member possessing a proximal cam surface, which interacts with the distal cam surface of the nut, and which is adapted to receive distal force from the nut and impart distal force to a rod extending through the at least one wall aperture; wherein at least a portion of the spinal locking device is within the cavity defined by the collar wall. 
 
 
     
     
       12. The bone attachment collar of  claim 11 , further comprising a washer. 
     
     
       13. The bone attachment collar of  claim 11 , further comprising:
 a washer having a beveled surface at a distal end of the washer, wherein the beveled surface abuts the head of the bone fastener, and 
 wherein the clamp member further comprises a distal surface, at least a portion of which is planar, convex or concave, and is adapted to engage the rod extending through the at least one wall aperture. 
 
     
     
       14. The bone attachment collar of  claim 11 , further comprising:
 a washer having a beveled surface at a distal end of the washer, wherein the beveled surface abuts the head of the bone fastener, wherein the beveled surface is planar frustoconical; and 
 wherein the clamp member further comprises a distal surface, at least a portion of which is concave, and is adapted to engage the rod extending through the at least one wall aperture.